Liquid crystal optical devices have merits such as low power consumption, small thickness, light weight, etc., and they are widely used for many electronic devices such as cellphones, digital cameras, portable information devices, TVs, etc. Among these, in recent years, liquid crystal optical devices are proposed, in which the electric field is controlled to control alignment of liquid crystal molecules thereby to change a light-scattering state.
Patent Document 1 discloses a liquid crystal optical device wherein a polyimide thin film for vertical alignment is formed on a pair of substrates provided with electrodes, a mixture of a liquid crystal and an uncured curable compound is sandwiched between the substrates, and the curable compound is cured by light exposure in a state where the mixture shows a liquid crystal phase, to form a liquid crystal/curable composite layer. Further, Patent Document 2 discloses a liquid crystal optical device having an electrooptical functional layer containing a liquid crystal and a polymer, obtained in such a manner that a liquid crystalline mixture containing a specific bifunctional polymerizable compound and non-polymerizable liquid crystalline composition is sandwiched between a pair of substrates provided with electrodes, and the polymerizable compound is polymerized to form a polymer in a state where the mixture shows a liquid crystal phase. Patent Document 3 discloses a scattering type display cell comprising a polymerized liquid crystal monomer (a) and a low molecular liquid crystal material (b), wherein the polymerized liquid crystal monomer (a) constitutes a cross-linked network, and around this network, the low molecular liquid crystal material (b) constitutes a continuous phase to form an electrooptical functional layer.
A liquid crystal optical device using a liquid crystal polymer composite of a transmission/scattering operation mode employs a system such that the liquid crystal polymer composite is sandwiched between a pair of substrates provided with electrodes, and a voltage is applied to the electrodes to change optical properties of the liquid crystal, and such a device is also called a polymer dispersed liquid crystal device or a dispersed liquid crystal. Unlike a conventional TN mode liquid crystal optical device or the like, the transmission/scattering liquid crystal optical device does not require a polarizing plate in principle, and accordingly its absorption loss of light is small, it has high scattering properties, and its light utilization efficiency is high as a whole. By making use of such properties, it is used for light control glass, an optical shutter, a laser equipment, a display device, etc.